US 7,002,986 B1 · Mapping arbitrary signals into SONET

Abstract

A synchronizer/de-synchronizer maps continuous format signals of an arbitrary rate into frames of pre-selected single common rate, such as SONET frames, with no bits changed and very little jitter or wander added. In this way, the continuous format signal may be carried transparently as a tributary of a SONET network. Each frame comprises a definite number of fixed stuff bits, including transport overhead bits and reminder fixed stuff bits. A frame also comprises an adjustable number of adaptive stuff bits, resulting from the phase difference between the arbitrary rate and the common rate. A mapping function is performed in a tributary unit shelf of a SONET transport shelf, and the reverse mapping function is performed in a similar way at the far end of a SON ET connection. The stuff bits are spread uniformly within the frame.

Claims28

Dependent claims

A method for transmitting a continuous digital signal of an arbitrary rate R1 over a synchronous network, comprising:

selecting a fixed length container signal of a rate R, where R is higher than said arbitrary rate R1 of said continuous signal;
and
at a transmit site, adaptively distributing the bits of said continuous signal into valid locations of a frame of said container signal and providing stuff bits into invalid locations,
wherein said invalid locations are uniformly interspersed across said frame.

1 more element

A synchronizer for adaptively mapping a continuous format signal of an arbitrary rate for transport over a synchronous network, comprising:

a data recovery unit for recovering from said continuous format signal, a stream of data bits and a data clock indicative of said arbitrary rate;
a receiver buffer unit for receiving said stream of data bits, determining a phase difference between said arbitrary rate and the rate of a frame of said tributary, and generating a control function β;
a mapping unit for extracting said stream of data bits from said receiver buffer unit at a mapping clock rate, and adaptively inserting stuff bits and said data bits into said frame at a block clock rate according to said control function β.

Dependencies are inferred from the claim text.

Mapping arbitrary signals into SONET

Life of this patent

Mapping arbitrary signals into SONET

Life of this patent

Abstract

Claims28